Add verification jobs for ccsdk/distribution

Add verification jobs for ccsdk/distribution

 - replace existing CCSDK CSIT jobs with project-specific CSIT job
 - add docker snapshot and docker staging jobs - snapshot images are
   still being done with maven, but tagging the images with STAGING
   is moved from maven to plain shell script (both of these have been
   implemented in https://gerrit.onap.org/r/c/ccsdk/distribution/+/116082)
 - add maven docker snapshot job template to support UNIQUE_DOCKER_TAG
 - note that this commit requires
   https://gerrit.onap.org/r/c/ccsdk/distribution/+/116082 to work
   properly in review and merge verification phases!
 - note also that this is not final commit related to this change
   as the maven docker template is still named with -PoC postfix
   and original artifact builds still remain triggered by review
   separately (the latter should be ultimately replaced by or
   included in review and merge verification jobs)

Issue-ID: CCSDK-3018, CCSDK-3019
Signed-off-by: Lasse Kaihlavirta <l.kaihlavirt@partner.samsung.com>
Change-Id: Id4c922e180c9d0ddadae6c99632d6ff6cdcbb59f